This report includes work arising from the following clinical protocols: NCT00030147, NCT00060736, NCT00001231, and NCT00001322. Our findings to date show that PMD is accompanied by a decreased QOL, decreased social adjustment and impaired role functioning comparable to depression occurring at other stages of a womans life. However, neither perimenopausal reproductive status alone nor the presence of hot-flushes had a significant negative impact on QOL measures. Nonetheless, it remains unclear whether the clinical characteristics we identified reflect pre-existing risk factors for PMD or the effects of a current depression. Preliminary data from our longitudinal study of women transitioning through the menopause clarifies this relationship in part. We examined whether the changes in negative life events and declines in QOL measures observed in cross-sectional studies were antecedents of PMD or reflect the effects of the presence of depression. We prospectively evaluated healthy women longitudinally across the menopause transition. Seventy-six asymptomatic, premenopausal women, ages 41-55 years, were monitored longitudinally for an average of 5.2 years until 6-12 months after their final menses (FMP). Outcome measures included the Structured Clinical Interview for DSM-IV (SCID), as well as standardized measures of QOL and life events. Twenty-nine episodes of major or minor depression occurred in twenty-three women, twenty-seven of these episodes occurred in the 2-years surrounding the FMP. Thus, confirming previous reports of the clustering of depressions during the late menopause transition a time associated with declining levels of ovarian estradiol secretion. During the four years prior to the FMP, compared to women who remained asymptomatic, women with PMD reported significantly lower life satisfaction in PMD but did not report significant differences in overall QOL, marital satisfaction, experience of personal loss, or negative life events. These data suggest that negative life events and decreased QOL/marital dissatisfaction do not uniformly precede the onset of PMD. Further, the relative absence of antecedent social or environmental events in PMD suggests a more specific role for hormonal events in the triggering of PMD. Preliminary findings from this longitudinal study also suggest that declining adrenal androgens (i.e., dehydroepiandrosterone) and progesterone-derived neurosteroids (i.e., allopregnanolone) could contribute to this risk for PMD. Fifteen additional women should complete this study over the next 1-2 years and at that time we will be better able to characterize the roles of these hormones in the risk for PMD. A role of estradiol withdrawal in the onset of mood disorders in some perimenopausal women has been suggested indirectly by the clustering of depressive episodes during the late menopause transition (the stage of ovarian aging associated with maximal decline of ovarian estradiol secretion) and by estradiols antidepressant efficacy in PMD. Additionally, we have completed a subsequent placebo-controlled study examining the effects on mood and behavior in women with PMD of estradiol and two compounds: the selective estrogen receptor (ER) modulator (SERM), raloxifene and a phytoestrogen (plant-derived estrogen-like compounds). In this study we replicated our previous findings that estradiol therapy is effective in the treatment of PMD; however, neither raloxifene nor the phytoestrogen showed significant effects on symptoms in PMD. Nonetheless, there is no direct evidence that estradiol withdrawal precipitates depressive episodes in those women who develop PMD. In our hormone manipulation studies, we evaluated the effects of the acute withdrawal of estradiol therapy in asymptomatic postmenopausal women with and those without a past PMD. In this study, asymptomatic postmenopausal women who experienced a depression during the menopause transition and asymptomatic postmenopausal women with no past depression received a standard dose of estradiol (100 mcg per day). After three weeks all women were randomly assigned under double-blind (DB) conditions to either continue estradiol or switch to placebo (estradiol withdrawal). If estradiol withdrawal was a relevant physiologic event to trigger depression, then one would predict that depressive symptoms would develop in those women randomized to placebo. Additionally, if women who develop depression during the perimenopause are differentially susceptible to the mood destabilizing effects of estradiol withdrawal, then mood symptoms should emerge in the women with past PMD but not the controls randomized to DB placebo. Results demonstrate that estradiol withdrawal induces depressive symptoms in women with past PMD (n = 26), but not in those without such a history (n = 30). Women with past PMD (but not those without past PMD) who were crossed over from estradiol to placebo (i.e., estradiol withdrawal) experienced a significant increase in depression symptom severity. Women with past PMD who continued on estradiol and all control women remained asymptomatic. Importantly, women with past PMD and control women had similar hot-flush severity and plasma estradiol levels during placebo and, therefore, neither differences in hot-flushes (and the attendant sleep-disturbance) nor peripheral estradiol levels account for the differential response to estradiol withdrawal. In women with past PMD, the recurrence of depressive symptoms during blinded hormone withdrawal suggests that normal changes in ovarian estradiol secretion can trigger an abnormal behavioral state in these susceptible women. These data also suggest that women with a history of PMD should be alert to the risk of recurrent depression when discontinuing hormone therapy. In collaboration with David Goldmans laboratory at NIAAA, we are investigating the effects of estradiol withdrawal on gene expression (whole transcriptome RNA-seq) in lymphoblastoid cell lines (LCLs) obtained from women with past PMD and controls who had the presence and absence, respectively, of estradiol withdrawal-induced depressive symptoms confirmed in the clinical study. These studies are performed before and after estradiol withdrawal in LCLs derived from women with past perimenopausal depression (PMD). The goal is to understand possible cellular basis for the differential behavioral response to estradiol withdrawal that was previously demonstrated in our hormone manipulation protocol. Preliminary findings of differential gene expression revealed 534 significant differential gene expression changes between women with past PMD and those with no past PMD after E2 withdrawal, as well as several molecular pathways that appear to be differentially altered in women with PMD. Of these genes, two are of particular interest in PMD: the gene CXCL10, which has been previously linked to cardiovascular disease, is significantly upregulated in women with PMD and the gene CYP7B1, an enzyme which is responsible for the metabolism of the steroids DHEA and pregnenolone (as well as oxysterols, bile acid metabolites with actions on the brain), is also significantly upregulated in women with PMD. Finally, in a recent FDA-approved protocol, we will explore whether the estradiol withdrawal signal is mediated by ER alpha or beta (or both) by employing a selective ER beta agonist. These data could identify a promising new class of therapeutic agents that are safer and more acceptable than estrogen and potentially lack the side effects or withdrawal syndromes associated with traditional psychotropics. Additionally, it is possible that the selectivity of these compounds for estrogen receptor alpha and beta may identify the mechanisms of efficacy of estradiol on specific target symptoms.